Later, when Dex goes to Galuzzo's house, he discovers that although the guy isn't the Brain Surgeon, he is a freaking cannibal (which horrifies even Dexter).

Q. What is it actually in real life?

A. A shopping mall.

Q. Where can I find it in real life?

A. This is the Los Cerritos Center, an enclosed mall located just east of the 605 Freeway at South Street, in the city of Cerritos, CA.

That's near the intersection of the 91 & 605 freeways, northeast of the city of Long Beach, and east of Lakewood.

They set up a fake "Work Out City" kiosk in the mall corridor that runs from east to west.

The kiosk was in front of The Gap and Banana Republic, between two real kiosks (Verizon and Sunglass Hut).

This shoot marks a couple of firsts for Dexter.

I believe this is the first time
in eight years that they've shot inside an actual mall (which is kind
of odd, when you stop think about it, since Miami certainly has its fair
share of enclosed malls).

And it's also the first time they've shot in Cerritos.

This is an artist rendering of the mall's east entrance, from their website:

First, Heather,
who works at the Cerritos Mall (right next to where they were filming)
emailed me the day before to let me know they were planning to shoot
there at 2 PM. Afterward, she sent me a photo that her friend Jenna shot of the fakeWork Out City kiosk they had set up in front of her store:

Meanwhile, one of my regular tipsters, Ellen,also
went to the mall during the shoot, but found the security tight by
then, making it hard to get a photo. She still managed to snap a
photo looking southeast in the mall, towards the kiosk. It gives
you a good perspective of just where in the mall the kiosk was located
(we're looking southeast in the photo below):

And last, but certainly not least, Ericmanaged to capture this shot of Michael C. Hall relaxing between takes: